High frequency electron discharge device having structural portions of a binary copper-iron alloy with 0.4 to 4.5% by weight of iron



Jan. 9, 1968 FlEDOR 3,363,137

HIGH FREQUENCY ELECTRON DISCHARGE DEVICE HAVING STRUCTURAL PORTIONS OF A BINARY COPPER-IRON ALLOY WITH 0.4 T0 4.5 BY WEIGHT OF IRON Filed Dec. 30, 1963 4 Sheets-Sheet l INVENTOR ADOLPH J. FIEDOR BY W ATTORNEY Jan. 9, 1968 A. J. FIEDOR 3,363,137

HIGH FREQUENCY ELECTRON DISCHARGE DEVICE HAVING STRUCTURAL PORTIONS OF A BINARY COPPER-IRON ALLOY WITH 0.4 T0 4.5% BY WEIGHT OF IRON Filed Dec. 30, 1963 4 Sheets-Sheet 2 INVENTOR ADOLPH J FIEDOR ATTORNEY Jan. 9, 1968 FlEDoR 3,363,137

HIGH FREQUENCY ELECTRON DISCHARGE DEVICE HAVING STRUCTURAL PORTlONS OF A BINARY COPPER-IRON ALLOY WITH 0.4 T0 4.5% BY WEIGHT OF IRON Filed D60. 30 1963 4 Sheets-Sheet 5 INVENTOR ADOLPH J. FIEDOR BY%7%Q ATTORNEY u Jan. 9, 1968 A. J. FIEDOR 3,363,137

HIGH FREQUENCY ELECTRON DISCHARGE DEVICE HAVING STRUCTURAL PORTIONS OF A BINARY COPPER-IRON ALLOY WITH 0.4 TO 4.5% BY WEIGHT OF IRON 4 Sheets-Sheet 4 Filed Dec. 30 1963 INVENTOR.

ADOLPH J. FIE DOR Patented Jan. 9, 1968 19 Claims. c1. 31s 3.s 10

ABSTRACT OF THE DISCLOSURE High frequency electron discharge devices such as for example klystrons, traveling wave tubes, magnetrons, cross-field amplifiers, etc. have enhanced strength characteristics without encountering deformation of structural portions during brazing operations when structural portions of the device are made from a binary copper-iron alloy with 0.4 to 4.5% by weight of the alloy, being iron.

The present invention relates in general to electron discharge devices and more particularly to high frequency velocity modulated electron discharge devices, such as klystrons, traveling Wave tubes, magnetrons, etc.

It can probably safely be said that virtually all high frequency electron discharge devices presently in use are constructed of materials having high thermal and electrical conductivity properties which generally includes copper of the OFHC vzuiety (oxygen free high conductivity copper). The utilization of OFHC copper for electron tube bodies and cooling fins, etc., is necessitated for thermal and electrical reasons, such as the dissipation of heat generated in the tube during operation and the necessity for having high thermal conductivity in most instances. However, OFHC has drawbacks with regard to strength and it has been found that during operations at adverse vibratory conditions, such as for example, airborne applications, copper of the OFHC variety is structurally inadequate in certain instances. Examples of the inadequacy of OFHC are found in the occurrences of vacuum leaks for example, such as caused by hydrogen cracking along the boundaries of copper. Mounting a klystron for example, to what may be termed redundant support points, and then subjecting the klystron to vibratory motion in regard to these points often causes distortion of the tube structure and resultant detuning of the cavities of the tube if it is a klystron, vacuum leakage, etc. Furthermore, generally speaking, every piece of copper that is utilized in electron discharge devices is subjected to a brazing operation at 1000" C. or above which leaves the metal in a dead soft annealed condition. No known conventional alloys of copper exist which Will maintain their strength after this treatment except high alloys such as Monel or Cupronickel in which the desirably high thermal or electrical conductivity is lost. Because of the low strength of the annealed copper, electron tube parts must be designed to be much larger and heavier than if they were made of stronger material. Furthermore, as mentioned above due to the softening of annealed OFI-IC which is conventionally utilized as an electron tube body material extremely difficult fabrication problems are encountered by the tube builder and special brazing jigs and tools are required in order to minimize the danger of deformation of high tolerance cavities, headers, drift tubes, etc. during the process of building a finished tube. Prior art schemes for improving the strength of tube parts utilized such approaches as employing steel having copper plating on the internal portions thereof such as cavities in the case of klystron type tubes. This approach provided a combination of high strength and good electrical conductivity but suffered the disadvantage of poor thermal conductivity from the copper-steel boundary outwardly to the external portions of the tube. This of course required such undesired solutions as the employment of complex and costly fluid cooling techniques to remove heat from the interior portions of the tube in order to stay within the design limits.

Therefore, a constant search for materials for electron discharge device tube bodies and cooling portions thereof and waveguide portions therefore is constantly being made by designers of high frequency velocity modulated electron discharge devices.

The present invention provides a solution to the afore mentioned problem in the form of a copper-iron alloy. This copper-iron alloy contains basically copper plus proportions of iron ranging from 0.4 to 4.5% by weight. This material has been found to be extremely easy to mass produce and provides high strength properties in addition to retaining to a high degree the high thermal and electrical conductivity properties of copper. Investigation has determined that the copper-iron alloy of the present invention retains a great deal of strength even after being subjected to brazing operations of 1000 C. or better. Therefore, it is quite evident that the copperiron alloy of the present invention while providing increased strength and only a minimal loss of thermal and electrical conductivity provides the long sought solution to the problem of obtaining a higher strength tube body material, without appreciable loss of thermal and electrical conductivity. Furthermore, the copper-iron alloy of the present invention permits bakeout operations in the vicinity of 500600 C. and brazing operations of about 1040 C. without appreciable loss in strength. The resultant beneficial advantage derived through the utilization of the novel alloy of the present invention in high frequency velocity modulated electron discharge devices, is the ability to more easily and more economically construct such devices. Furthermore, the present invention provides a considerable improvement in tube strength without sacrificing appreciable thermal conductivity in comparison to tubes made of copper. Furthermore, the present invention also includes the concept of providing certain portions of electron discharge devices utilizing a copper-iron alloy therein as taught herein with a coating of high thermal and electrical conductivity such as copper, etc. For example, the drift tubes, headers and cavity walls of a klystron having a base material of copper-iron as taught herein are advantageouslycopper clad to present high electrical conductivity for the RF. energy while simultaneously retaining the strength and slightly lower thermal and electrical properties of the base copper-iron alloy as disclosed herein. The present invention is also advantageously employed in electron tubes which find use in systems which undergo vibration stresses as mentioned above. For example, if the system resonance is within certain limits and it is seen that electron discharge devices madeof primarily of OFHC, for example, are resonated and tend to be microphonic when utilized in such a system, then if raising the natural resonance of the device above the system limits can be accomplished microphonics will be greatly reduced. It is known that the strength of a material is proportional to the natural mechanical resonance of the material. The copper-iron alloy as disclosed by the present invention can advantageously be employed to move the natural resonance of an electron discharge device up and beyond the upper limits of the system resonance within which it is to be utilized. This of course affords the designer greater flexibility in designing lower noise systems.

An object of the present invention is to provide high frequency electron discharge devices of the velocity mod ulated type with portions thereof made of a copper-iron alloy as disclosed herein.

A feature of the present invention is the provision of a high frequency electron discharge device with a tube body made of a copper-iron alloy having 0.4 to 4.5% iron by weight.

Another feature of the present invention is the provision of a high frequency electron discharge device having cooling fins wherein the cooling fins are made of a copper-iron alloy having 0.4 to 4.5% iron by weight.

Another feature of the present invention is the provision of a high frequency electron discharge device having waveguide transmission means integral therewith wherein said waveguide transmission means are made from a copper-iron alloy wherein iron comprises 0.4 to 4.5 of the alloy by weight.

Another feature of the present invention is the provision of utilizing an age hardened copper-iron alloy for portions of electron discharge devices wherein iron comprises 0.4 to 4.5 of the alloy by weight.

Another feature of the present invention is the provision of utilizing high electrical and thermal conductivity coatings on certain portions of the devices set forth in the previous features such as, for example, the cavity walls, drift tubes and headers of a multicavity klystron type of electron discharge device.

Other features and advantages of the present invention will become more apparent upon a perusal of the following specification taken in conjunction with the following drawings wherein:

FIG. 1 is a perspective view of an electrostatically focused four cavity klystron amplifier embodying features of the present invention;

FIG. 2 is a side view partially in section of the structure shown in FIG. 1 taken alone'line 22 in the direction of the arrows;

FIG. 3 is a perspective view of a reflex klystron oscillator embodying features of the present invention;

FIG. 4 is a side view partially sectioned of the structure shown in FIG. 3 taken along line 4-4 in the direction of the arrows;

FIG. 5 is a longitudinal cross-section view of a typical form of multiple cavity klystron amplifier utilizing the teachings of the present invention;

FIG. 6 is a longitudinal cross-section view of a magnetron tube which utilizes the present invention;

FIG. 7 is a longitudinal cross-section view of a typical form of traveling wave tube utilizing the teachings of the present invention; and

FIG. 8 is a graphical representation of Vickers hardness numbers over a range of temperatures for various materials and conditions as explained in detail hereinafter.

Although high frequency velocity modulated tubes shown in the drawings are specific forms of klystrons, magnetrons, traveling wave tubes and while such tubes realize particularly the advantages accruing from the present invention, other high frequency tubes may similarly benefit from the teachings of the present invention.

Referring now to FIGS. 1 and 2, an electrostatically focused multicavity klystron amplifier made in accordheader members 15. The walls of the drift tube 13 are parallel to the axis of the longitudinal bore 12 and an electron beam passing therethrough.

A narrow, annular anode header 16 having a resonator grid 17 positioned in the center aperture is fixedly secured, as by brazing, in one end of the longitudinal bore 12 of the central body portion 11. Within the opposite end of the longitudinal bore 12 of the central body portion 11 is an annular header 18 with a resonator grid 19 positioned on the end of a grid tube portion projecting axially from around the aperture therethrough.

Anode header 16 and the first annular header 15 define an input cavity resonator 21 within the central body portion 11. The first, second and third annular headers 15 define cavity resonators 22; and the third annular header 15, and annular header 18 define an output cavity resonator 23.

A beam generating assembly 24 is adapted to project an electron beam axially through the central body portion 11 is vacuum sealed, as by brazing to the central body portion 11.

The beam collector assembly 25 is fixedly secured, as by brazing, to the ends of the. central body portion 11 adjacent to the annular header 18. The beam collector assembly 23 is provided on the exterior thereof with a plurality of annular cooling fins 26 whereby the tube can be cooled.

Identical output waveguide assemblies 27, 28 are secured to the central body portion 11 and respectively communicate with the input cavity resonator 21 and the output cavity resonator 23 through milled openings 29 within the central body 11. The outwardly projecting end of each of the waveguide assemblies 27, 28 is provided with a Waveguide flange 31 which carries a wave permeable window 32 such as of ceramic, sealed therein by a window frame member 33.

A tuner block 34- is provided in one side of the central body portion 11 and provides a movable tuner diaphragm, not shown, for each cavity resonator. Each of the tuner diaphragms are movable by means of a tuning screw 35. The metal utilized for cooling fins 25 and waveguide assembly 27 and flanges 31 will be discussed hereinafter.

Referring now to FIGS. 3 and 4, there is shown a reflex klystron which embodies the present invention. This reflex klystron comprises a main body block 46 with a longitudinal bore extending therethrough. An electron gun assembly 47 and reflector assembly 48 are vacuum sealed on the body at opposite ends of the bore. Two drift tube headers or walls 49 and 51 and associated resonator grids 52 are secured within the body bore and serve to form the cavity resonator. This reflex klystron can be tuned by means of a side wall tuner 53 in a well known manner, the output being coupled out from the cavity resonator through an iris opening in the body and through the waveguide flange 54. The main body, header and flange materials of this reflex klystron will be discussed below along with the materials of the klystron shown in FIGS. 1 and 2.

FIG. 5 depicts a magnetically focused type of electron discharge device as, for example, a magnetically focused multicavity klystron tube of the type shown therein, wherein the utilization of the copper-iron alloy as taught by the present invention is advantageously employed. This klystron tube is similar to one shown and described in US. Patent No. 2,963,616 issued Dec. 6, 1962, to R. B. Nelson et al., and will not be described in detail herein except to the extent necessary to indicate the utilization of the present invention therein. This klystron tube, in general, includes cathode structure 55, an electron beam collector structure 56, a multi-cavity R.F. interaction structure 57, and the electron magnetic focusing structure 58. RF. output of the klystron depicted in FIG. 5 is taken from waveguide through wave permeable Window 67 which is mounted in flange member 64 as shown. A transformer section 66 serves to provide optimum impedance to the RF. energy over the tunable range of operation of the tube. The klystron depicted in FIG. 5 includes as part of the interaction structure the main body wall 59, cavity 7 5 end walls or header 61, and drift tube 62. Conventional high permeability magnetic pole pieces 63 and 64 are positioned at the separate ends of the interaction structure. Those portions of the multicavity klystron amplifier depicted in FIG. 5 which are made from the copper-iron alloy as taught by the present invention will be described in detail hereinafter.

The utilization of the copper-iron alloy disclosed in the present invention in a cross field device or magnetron is exemplified in FIG. 6 which discloses, in longitudinal cross-section, a typical form of magnetron type more clearly described and shown in US. patent application Ser. No. 105,715, now Patent No. 3,169,211, titled, Magnetron, filed Apr. 26, 1961, in the name of Jerome Drexler et al. This specific form of magnetron is sold as model SFD-303 by the S-F-D Laboratories of Union, N. J. The main body assembly of this magnetron is designated by reference number 81 to which there is suitably brazed the anode assembly 82 and cathode assembly 83 including the cylindrical cathode emitter 84. The magnetron interaction region is defined by the cylindrical space between the outer periphery of the cylindrical cathode emitter 84 and the inner tips of a circular array of radially inwardly directed anode vanes 85 or wave supporting structure, which are carried at their outer peripheries from the inside surface of a cylindrical anode wall 86. As is well known in the art, the spaces between adjacent vanes within the interior of the cylindrical anode wall 6 define the plurality of inner cavity resonators which interact with the electron beam or stream of this device. The outer cavity resonator 87 is formed in the main body block 88 and is coupled to the inner resonators defined by the vanes 85 and walls 86 to coupling holes in the walls 86 in a well known manner. Output energy is extracted from the magnetron through the output coupling slot 89, waveguide 91 and vacuum sealed window structure 92. This known form of magnetron incorporates a magnetic circuit or structure which provides a tubular shaped magnetic field extending between the inner ends 93, 94 of the two cylindrical pole pieces 95 and 96, these pole pieces being coupled to a C-shaped permanent magnet (not shown) via cylindrical magnetic members 97, 98 and 98'. The particular portions of the magnetron depicted in FIG. 6 which are made from the copper-iron alloy disclosed by the present invention will be described in more detail hereinafter.

Directing our attention to FIG. 7 there is shown therein a traveling wave tube of the backward wave oscillator type (BWO) wherein certain portions thereof are made from the copper-iron alloy of the present invention. The particular operating characteristics of the BWO shown in FIG. 7 will not be described herein since reference to US. Patent No. 2,991,391 by William L. Beaver, filed July 24, 1957, fully describes the BWO shown in FIG. 7. However, in order to more adequately describe the present invention reference will be made to portions of the backward wave oscillator depicted in FIG. 7 which are particularly pertinent to the present invention. In this respect, there is depicted in FIG. 7 a BWO generally indicated by reference numeral 68, having a tube main body 69, a collector assembly 70 and an electron gun assembly 71 for projecting and directing a beam of electrons axially along the tube axis. An annular body extension member 72 surrounds an appreciable portion of the cathode assembly 73 as shown, and it is brazed to the inner extension. An annular anode and beam shaver member 76 having an elongated bore centrally disposed therein is secured within the main body member 69 and has an accelerating or anode grid 77 secured over the lower end of the bore in spaced-apart relationship from the current control grid 78 of the tube.

Directing our attention to the RF. output section depicted in FIG. 7, there is shown a waveguide 79 extending from and suitably brazed in vacuum sealed relationship to the main body 69. A frame member 81 is secured to the outer end of the waveguide 79 and is arranged to be bolted to a matching frame member 82 and an approximately elliptical ceramic window is sandwiched between the two frame members. An exterior waveguide 83' is secured to the outer frame member 82' and extends outwardly to a waveguide flange mounting member 84' as shown. This essentially completes the description of those portions of the backward wave oscillator shown in FIG. 7 which are pertinent to the invention as disclosed herein. The particular materials employed in the BWO depicted in FIG. 7 which are pertinent to the present invention will be described hereinafter.

FIG. 8 depicts a graphical portrayal of plots Vickers hardness numbers using a DPH (diamond point hardness)/5 kg. load versus annealing temperatures for various tube body materials including several types of copperiron alloy disclosed in the present invention. The materials tested in the comparisons depicted in FIG. 8 were rolled sheet stock of equivalent dimensions. The articular materials tested in the comparison shown in FIG. 8 were particularly suitable or cooling fin portions of an electron discharge device. The Vickers hardness was measured at room temperature on the materials and on specimens which were annealed in hydrogen for one hour at various temperatures. The results are as follows: the examination of characteristic A which is representative of commercial OFHC shows a substantial decline in hardness as annealing temperatures are increased beyond 400 which is below conventional bakeout temperatures. It is seen that normal OFI-IC has considerably reduced strength and is practically speaking, in a dead-soft annealed condition. Characteristic B is representative of a commercial alloy Amzirc. This material is essentially OFHC and A zirconium by weight and is expensive. It is seen that Amzirc has considerably higher hardness characteristics at lower annealing temperatures than OFHC copper. However, at high temperatures which are representative of the brazing conditions encountered in processing electron discharge devices, Amzirc has considerably reduced hardness and is practically speaking equivalent to OFHC. Characteristic C depicts one example of the copper-iron alloy of the present invention and it is seen that the 2% iron, 98% copper alloy by weight produces a hardness which is substantially above that of OFHC at room temperatures. As annealing temperatures increase the 2% copper-iron alloy retains appreciable proportions of its initial hardness. At brazing temperatures above 1000 C. it is seen that the 2% copper-iron alloy has a Vickers hardness of about 75 which is appreciably greater than the 27 or so registered by conventional OFHC at temperatures in excess of 1000 C. Characteristic D is representative of another example of the copper-iron alloy of the present invention which contains 4% iron and the remainder copper by weight. It is seen that there is substantially little difference between 2% and 4% iron by weight of the composition as taught by the present invention with regard to hardness characteristics over brazing or annealing temperatures up to 1000 C. The copper-iron alloy (2% iron) begins dropping after 200 but maintains a fairly high level of hardness after this and actually rises to approximately 77.3 at 1000 C. after reaching a low of approximately 69 at 800 C.

Further tests were made to determine whether the copper-iron alloy as disclosed in the present invention is age hardenable and several small specimens were water quenched from 1040 C. and reheated for one hour at temperatures at between 400 and 800 C. The results are plotted in FIG. 8. Characteristic E is representative of a copper-iron alloy wherein 2% iron by weight is utilized and the specimen is quenched and aged as described above. Characteristic F is representative of 4% copper-iron alloy quenched and aged as described above. It is evident that in both the 2% and 4% quenched and aged copper-iron alloy specimens that there is reduced hardness at lower annealing temperatures but that at temperatures in excess of 600 C. there is very little difference between the quenched and aged specimens and the simple annealed 7 specimens depicted in characteristics C and D, with reg-ard to Vickers hardness.

It is thought that the results depicted in FIG. 8 with regard to retention of strength of the material which is utilized in the electron tubes of the present invention is also indicative of the compression and tensile strengths of the material. The preparation of the copper-iron alloy having the percentages of 0.5 to 4.5% iron and the remainder copper is extremely simple and will be described herein-after. The copper-iron alloy described herein is simply prepared by melting the desired portion of copper preferably electrolytic or other high purity types of commercial copper, in a suitable container such as a crucible and dissolving therein the desired portion of iron which can vary from 0.5 to 4.5% by weight of the alloy. The iron to be dissolved may take the form of granules, blocks, powder or any suitable form and in each case the complete dispersion of the iron within the stated percentages is easily accomplished at melt temperatures of approximately 1450 C. for minute periods. The resulting ingot may then be rolled and treated in any other conventional fashion. Of course, the ultimate shape which the alloy of the present invention takes depends upon its particular usage in an electron tube.

The copper-iron alloy previously described is advantageously employed in the electron tubes depicted herein in the following manner. In the klystron amplifier of FIGS. 1 and 2 and the reflex klystron oscillator of FIGS. 3 and 4 the copper-iron alloy of the present invention is advantageously employed to form the entire tube bodies respectively of the klystrons depicted in FIGS. 1 through 4. The copper-iron alloy can also be advantageously be utilized to form the cooling fins both of the body portion and the collector portion of the klystron of FIGS. 1 and 2 and also the flange or waveguide portions of the klystrons depicted in FIGS. 1-4. Naturally, the tube designer will have to consider the small losses in thermal and electrical conductivity which result from the use of the copper-iron alloy of the present invention. These losses are rather insignificant, however, the present invention includes the use of high conductivity coatings such as copper, etc. on those portions of an electron discharge device which demand good electrical conductivity. This would include drift tubes, headers, internal cavity walls and any other portions of a klystron wherein even the small losses in electrical conductivity introduced by the utilization of the copper-iron alloy of the present invention could not be tolerated. Any conventional metal coating techniques such as, for example, electroplating, may be utilized to deposit the high conductivity coating. The above discussion also applies to any other electron discharge device utilizing the cop per-iron alloy as taught by the present invention.

In the multicavity klystron device magnetically focused such as depicted in FIG. 5, the following portions thereof are advantageously made from the copper-iron alloy of the present invention. The tube main body 57, the output waveguide including the transformer section 65, 66 and waveguide flange member 64 are advantageously made from the copper-iron alloy of the present invention. Furthermore, the header portions 61 and the drift tube portions 62 may advantageously be made from the copperiron alloy of the present invention.

In the magnetron, depicted in FIG. 6, the main body portion 98, cooling fins 10d and waveguide member 91 are advantageously made from the copper-iron alloy of the present invention. Furthermore, the anode assembly 82 is advantageously made from the copper-iron alloy of the present invention.

Turning our attention to the backward wave oscillator depicted in FIG. 7 which is representative of the traveling wave type electron discharge device, the following portions thereof are advantageously made from the copperiron alloy of the present invention. Tube main body 69, waveguide 79, flange members 81', 82', waveguide 83 and external flange 84 and annular extension member 72 are advantageously made from the copper-iron alloy of the present invention.

It is to be understood that the copper-iron alloy described herein and employed'in the electron discharge devices depicted in FIGS. 17 may advantageously be incorporated in other electron discharge devices such as klystron oscillators, triodes, etc. and the present invention so contemplates. Conventional brazing materials which are utilizable with normal OFHC are likewise utilizable with the copper-iron alloy disclosed herein. A few exemplary electron discharge devices which can be advantageously constructed from the copper-iron alloy as dis-closed herein with or without the high conductivity coating thereon, on such portions thereof as indicated hereinabove are found in US. Patents 3,021,447; 3,028,519; 3,051,866 and 2,- 965,794.

Since many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made Without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. An electron discharge device comprising, means for producing and projecting an electron beam along a predetermined path, means for providing beam-wave interaction disposed about said electron beam path and physically coupled to said means for producing and projecting said electron beam, means for extracting R.F. electromagnetic wave energy from said device coupled to said means for providing beam-wave interaction, said device for generating R.F. electromagnetic wave energy having at least some of the structural elements forming said device made from a binary copper-iron alloy wherein iron comprises 0.4 to 4.5% by Weight of the alloy.

2. An electron discharge device as defined in claim 1 wherein said device includes a tube main body, said tube main body having a cavity resonator adapted to pass an electron beam therethrough, said tube main body and said cavity resonator being terminated on the one end thereof by said beam producing and projecting means and on the other end thereof by a beam collecting means, said tube main body including said cavity resonator being made from said binary copper-iron alloy containing 0.4 to 4.5 iron by weight.

3. The electron discharge device defined in claim 1 wherein said device includes a slow wave structure surrounded by a tube main body, said tube main body being terminated on the one end thereof by said electron beam producing and projecting means and on the other end thereof by beam collecting means and wherein said slow wave structure has radio frequency transmission means coupled thereto, and wherein said tube main body means are made from said binary copper-iron alloy containing 0.4 to 4.5 by weight of iron.

4. The electron discharge device defined in claim 1 wherein said device includes a tube main body forming a portion thereof, said main body having a wave supporting structure therein in wave energy exchanging relationship with saidelectron beam, magnetic structure formed within said body for directing a magnetic field having a substantial component thereof normal to the main direction of electrons thereof, said main body being made of said binary copper-iron alloy which is 0.5 to 4.5% iron by weight.

5. The electron discharge device as defined in claim 1 wherein portions of said device have a coating deposited thereon, said coating being made of a metal having higher electrical and thermal conductivity than said binary copper-iron alloy.

6. The electron discharge device as defined in claim 1 wherein said device includes a cavity resonator adapted to pass an electron beam therethrough, means defining cavity end walls for conducting electromagnetic waves,

and an interaction gap defined by a pair of drift tubes projecting from mutually opposing cavity end walls, said cavity resonator and said drift tubes being made from said binary copper-iron alloy which is 0.5 to 4.5% iron by weight.

7. The device as defined in claim 6 wherein said cavity resonator and said drift tubes have portions thereof provided with a metal coating deposited thereon, said coating being made of a metal having higher electrical and thermal conductivity than said binary copper-iron allo 8. The device as defined in claim 1 wherein said device includes, a main body, means for producing an electron beam within said body, said body having at least one cavity resonator formed therein in the beam path for electromagnetic interaction with the electron beam, said main body forming the side walls of said cavity resonator, header members forming the end Walls of said cavity resonator and adapted to pass an electron beam therethrough, said header members being made of said binary copper-iron alloy.

9. The device as defined in claim 8 wherein said header members have portions thereof provided with a metal coating deposited thereon, said coating being made of a metal having a higher electrical and thermal conductivity than said binary copper-iron alloy.

10. The device as defined in claim 2 wherein said cavity resonator has portions thereof provided with a metal coating deposited thereon, said coating being made of a metal having a higher electrical and thermal conductivity than said binary copper-iron alloy.

11. The device as defined in claim 4 wherein said wave supporting structure is made from said binary copper-iron alloy.

12. The device as defined in claim 11 wherein said wave supporting structure has portions thereof provided with a metal coating deposited thereon, said coating being made of a metal having a higher electrical and thermal conductivity than said binary copper-iron alloy.

13. The device as defined in claim 1 wherein said device has portions thereof forming cooling fins, said cooling fins being made of said binary copper-iron alloy.

14. The device as defined in claim 1 wherein said device includes a collector structure being made of said binary copper-iron alloy.

15. The device as defined in claim 1 wherein said device includes high frequency RF. transmission coupler means coupled thereto, said high frequency RF. transmission coupler means having portions thereof made from said binary copper-iron alloy.

16. The device as defined in claim 15 wherein said high frequency RF. transmission coupler means has portions thereof provided with a metal coating said coating being made of a metal having a higher electrical and thermal conductivity than said binary copper-iron alloy.

17. A high frequency klystron device comprising means for producing and projecting an electron beam along a predetermined electron beam path, means for collecting said electron beam disposed on the downstream end of said beam path and spaced from said beam producing and projecting means, means for electromagnetic interaction with said beam disposed intermediate said beam producing and projecting means and said beam collecting means in vacuum sealed relationship therewith, cooling fins disposed on said klystron device, said means for electromagnetic interaction including at least one cavity resonator forming a portion of said device, RF. transmission means coupled to said klystron device, said cavity resonator, said cooling fins and said R.F. transmission means being made from a binary copper-iron alloy wherein iron comprises 0.4 to 4.5 by weight of the alloy.

18. A high frequency electron discharge device of the traveling wave type having means for producing and projecting an electron beam along a predetermined electron beam path, means for collecting said electron beam disposed on the downstream end of said beam path and spaced from said beam producing and projecting means, slow wave circuit means for electromagnetic interaction with said beam disposed intermediate said beam producing and projecting means and said beam collecting means, a tube main body surrounding said slow wave circuit, cooling fins disposed on said traveling wave device, and RF. transmission means coupled to said device, said tube main body, cooling fins and RF. transmission means being made from a binary copper-iron alloy wherein iron comprises 0.4 to 4.5% by weight of the alloy.

19. A high frequency electron discharge device of the crossed field type comprising, a main body forming a portion of a vacuum envelope of said device, means for producing a stream of electrons in said main body, said main body having a wave supporting structure therein in wave energy exchanging relationship with said stream of electrons, magnetic structure formed within said body for directing a magnetic field having a substantial component thereof normal to the mean direction of travel of the electron stream and cooling fins disposed on said crossed field device, said main body and said cooling fins being made from a binary copper-iron alloy wherein iron comprises 0.4 to 4.5 by weight of the alloy.

References Cited UNITED STATES PATENTS 2,504,935 4/1950 Nichols --153 2,520,955 9/1950 Okress et al. 313-311 X 2,564,844 8/ 1951 Hodge 75153 2,687,490 8/1954 Rich et al. 31345 X 2,849,633 8/ 1958 Crapuchettes 3l345 2,854,332 9/1958 Bredzs et a1. 75-153 2,991,391 7/1961 Beaver 315-3.5

5 HERMAN KARL SAALBACH, Primary Examiner.

S. CHATMON, JR., Assistant Examiner. 

